Manufacture of catalysts



Patented Apr. 21, 1942 MANUFACTURE OF CATALYSTS Louis S. Kassel,Chicago, 111., assignor to Universal Oil Products Company, Chicago,Ill., a corporation of Delaware No Drawing. Application June 28, 1940,Serial No. 342,901

Claims. (01. 252-254) This invention relates to the manufacture ofcatalysts suitable for accelerating reactions containing materials suchas coals, lignites and shales. The preferred catalysts are preparedsynthetically by definite procedures which are specific in theproduction of catalysts of high activity for prolonged use under hightemperatureconditions of processing and regeneration.

A large number of hydrated oxides have been composited or compoundedwith silica gel according to various procedures whereby composites areformed which are utilized as catalysts innumerous reactions such ashydrogenation,

oxidation and other types as well as inthe hydrocarbon crackingreactions. These composites include various oxides of aluminum,chromium,

cobalt, manganese, nickel, copper, thorium, molybdenum, titanium,vanadium, zirconium and others. Although the methods of the presentinvention are applicable to the formation of formed particles fromcomposites of the above hydrous oxides with hydrated silica, theinvention is particularly directed to the formation of composites ofprecipitated hydrated silica with such hydrous oxides .as alumina and/orzirconia which composites are especially active in catalyzinghydrocarbon conversion reactions.

In one specific embodiment the present invention comprises animprovement in the manufacture of catalysts suitable for use inhydrocarbon conversion reactions to produce substantial yields ofgasoline having high antiknock value whereby particles of-the crackingcatalyst are formed by extruding an intimate mixture of the catalyticmaterial, a major proportion of which is in the finely divided orpowdery condition and a minor proportion is in the gel condition.

According to the process of the present invention, a mixture of hydrousoxides suitable for extrusion is prepared by intimately associating apart of the preparation in the finely divided or powdery condition andpart in the gel condi- 1 then be purified, or it may-have compositedover the usual procedure of extrudingonly the gel. The finely dividedmaterial is simpler to prepare, and easier to wash and purify than thecorresponding gel material. The water content can be regulated in themixture of finely divided material and gel more readily than in the gelalone so as to obtain a firm product while suflicient moisture ispresent to properly lubricate the dies.- The extruded material afterdrying and heating has greater crushing strength and develops fewercracks or fissures than corresponding product from gels alone.

The finely divided precipitated material and the gel may be ofessentially the same composition varying only in the physical structureand water content, or they may be of different composition. Hydratedsilica may be prepared in a finely divided condition where theindividual particles are very small and approach colloidal dimensions.This finely divided precipitate may therewith other hydrous oxidesbefore it is washed and purified. The hydrous oxides for example may beprecipitated in the presence of the finely divided hydrated silica andthe composite washed, either before or after partial drying withrelative ease as compared with the washing of corresponding materials inthe gel state. The gel which is intimately admixed with finely dividedprecipitate may be either a silica hydrogel or a hydrogel of a hydrousoxide such as alumina and/or zirconia, or a composite of these hydrogelsmay be used which partakes in the desired catalytic effects of thecatalyst preparation.

In the preparation of finely divided silica, a commercial grade of waterglass, for example,

- may then be added, while agitating, in suifici'ent tion. procedure hasseveral advantages proportions to precipitate the finely divided orpowdery .hydrafed silica. In the precipitation of the'hyd'rated silica,a precipitate of sodium silicate may form at, first which is thenconverted to hydrated silica. Finelydivided silica in the desired formremains in suspension for a relatively long time without any appreciabletendency of settling out. This finely divided bydrated silica may bewashed and purified, subsequently mixed with the gel component and thenextruded, or the suspension of the finely divided precipitate maybemixed with a salt of acid or alkaline reagent. In this case also. veryfinely divided precipitate is formed as a suspension distributed throughthe liquid when the sub stances added to bring about precipitation infinely divided form and the reactants are present under proper pHconditions and concentration.

Although silica hydrogel'or alumina hydrogel for example may be employedas the gel component of theextrusion mixtures, various gels may becomposited and used, and numerous methods may be employed in compositingthe gels. The

- components may be separately, concurrently or consecutivelyprecipitated. Generally speaking,

the primary and major component of the gel as well as of the finalcomposited catalyst, is a precipitated hydrated silica which is usuallyadmixed with a precipitated hydrous metal oxide such as alumina,zirconia or mixtures thereof and present in minor proportions. Accordingto one general method of preparation, the hydrated silica may beprecipitated from a dilute solution of commercial water-glass andsubsequently admixed with the remaining'hydrous oxide components with orwithout preliminary purification. The hydrated silica may be admixedwith the hydrous oxide components in any suitable manoxides maysometimes be'similarly washed. The washing is more difficult in the caseof the gels than in the case of the finely divided material, largervolumes of wash liquid are required, and more handling and/orequipment-is necessary. In the washing of the gel or the finely dividedprecipitate, they may be directed 'as an aqueous suspension to aconvenient form of filter such as a centrifugal filter or filter pressfor example wherein the large bulk of the liquid is removed and a filtercake is obtained. Since this filter cake, particularly in the case ofthe gels, is rather difiicult to wash in situ, one practice consists ofre-slurrying the filter cake in the washing agent and returning to thefilter, repeating this process if necessary until the materialissuitably washed. In the case of the finelydivided materialit may bepartially dried and the partially dried materials washed free from theundesired impurities by various methods.

The finely divided hydrated materials and the hydrogel which aresubstantially free from alkali metal impurities, are intimately mixed inthe desired proportions prior to extrusion by any suitable means. Theinvention is not restricted to a simple mixing procedure however sinceit is possible to prepare the finely divided portion as has beendescribed above and precipitate the hydrogel in an aqueous suspension ofthe finely divided component. The final composite may then consist ofmixtures of hydrated silica with other hydrous oxides such as those ofaluminum,

' zirconium, vanadium, thorium, chromium, or of her. Similarly as forthe finely divided precipigel may for example be immersed in solutionsof the metal salts and hydrous oxides deposited upon the hydrated silicagel by means of hydrolytic adsorption."

other metals which yield materials having catalytic and adsorbentproperties. Various proportions of the hydrated oxides may be present inthe finished product, the more frequent practice being to have minoramounts of added hydrated oxides and major proportions of hydratedsilicon dioxide. Thus, in the preparation of highly poroussilica-aluminacatalysts, 5 to 30% of hydrated alumina is distributed andvery intimately disposed in and on the surface of 95 to 70% of Ashasbeen indicated, the finely divided and the gel components are eachusually washed and purified. In order to produce refractory and stablecatalysts for prolonged use it has been found necessary where alkalimetal impurities such as sodium compounds have been incorporated intothe catalytic material during preparation to treat it at some stage ofits preparation to remove these alkali metal impurities. The

ponent of the added metal oxides. Thus hydrated silica may, for example,be washed with water "containing small amounts of hydrochloric acid oraluminum chloride, or finely divided hydrated sili ca may be partiallydried-and then washed in this manner, or hydrated silica with addedhydrated hydrated silicon dioxide. Smaller and larger proportions ofalumina and/or zirconia, or other hydrous oxides may also be similarlyused but not with equivalent catalytic effects.

The mixtures may be extruded in conventional extruding equipment underhigh pressure and the extruded material is usually cut into shortcylinders which are subsequently handled so as not to lose the identityof the individual par-" ticles whereupon they are carefully dried andthencalcined at approximately 1000 to 1600 F.

H. The average size of the extruded particles may vary within theapproximate range of 4-10 mesh, more or less, which is not restrictednecessarily to short cylindrical shapes since the shape of the productmay be modified for example as approach a spherical condition.

The catalysts of the present invention may be conveniently utilized incarrying out various types of hydrocarbon conversion reactions whenemployed as filling-material in tubes or may be disposed in trays or inchambers. A hydrocarbon oil fraction is usually heated to substantiallyreaction temperature and the vapors contact'ed with the stationarycatalyst masses. The

'. hydrocarbon vapors may be passed downward through the catalyst, andwhere large beds of catalyst are involved the passage of vapors may berestricted to definite paths rather than allowing the vapors to haveunrestricted contact with the large beds of catalytlcmaterial. Wherethis method is used, the temperature of. the contact materials while inuse and during regeneration may be controlled by various operatingproce-- dures or by heat .interchange devices. After the oil vapors havepassed over the catalyst as in catalytic cracking for example, theproducts may be separated into high boiling fractions unsuitable forfurther cracking and/or insufliciently converted fractions which may besubjected to further cracking treatment and the gasoline and gaseousproducts. The higher boiling fractions may be removed from the ,system,may be returned directly'to'admixture with the charging stock or may beprocessed in separate passes so as to ultimately obtain maximumutilization of. the charging stock in producing the gasoline product.

The following specific examples are givento illustrate applications ofthe process of the invention,,the activity of the catalyst preparationalso being indicated. The invention shouldjnot be considered as limitedto these examples of the process of manufacture or to these particularcatalyst'preparations since they are given as illustrative of thenovelty and utility of the 'in-' vention.

Example I A silica-alumina catalyst having approximately the followingcomposition, lOOSiOalOAlzOa.

may be prepared according to the following procedure.

In this preparation approximately 65% consists of finely dividedprecipitated hydrated silicaand 35% of silica-alumina. hydrogel. Twoparts by weight of commercial water glass containing 8 to 9% NaiO andapproximately 28% 'with acidulated water to remove alkali metal Thwashed precipitate is dried at impurities. approximately 225 F. and thedried material consists of a fluffy powder of very fine texture.

A silica hydrogel is separately prepared according to the same procedurewith the omission ofthe sodiumchloride. The silica hydrogel is alsowashed to remove alkali metal impurities but is not dried. The purifiedsilica hydrogel is high pressure.

suspended in a solution of aluminum chloride, the

aluminum chloride beirig present in sufficient proportions to yieldhydrated alumina in the amount indicated above with relation to thehydrated silica components. The hydrated alumina is precipitated by theaddition of ammonium hydroxide and the hydrated silica-alumina gel isfiltered and thoroughly kneaded with the dried powder under pressure andthe kneaded mixture extruded under high pressure. The extruded materialis cut into short cylinders and these are dried at a temperature ofapproximately 200 F. and the dried particles then calcined at atemperature of 1500 F. for approximately two hours.

Catalyst particles of this type when disposed in a reaction chamber andcontacted at an hourly space velocity of 2 with Pennsylvania gas oil va-.pors preheated to a temperature of approximately long time withoutsubstantial loss due to disinv tegrati'on of the particles.

Example 11 A silica-alumina-zirconia may be prepared as follows havingapproximately the formula SiOz.2A12Oa.5Zl'O2 and may'consist of 70% offinely divided precipitated hydrated silica and hydrated alumina while30% may consist of asilica-zirconia hydrogel. A finely dividedprecipitated hydrated silica is prepared as described in Example I andis-suspended in a soluticnof aluminum chloride in an amount which yieldsprecipitated alumina in the proportion above indicated. The hydratedalumina is precipitatedv by the addition of ammonium hydroxide and thesilica-alumina composite thus found is then filtered on a centrifugalfilter and dried at approximately 200: F. The dried material is washedwith acidulated water to substantially remove alkali metal impurities.The washed material is substantially dried and mixed with the gelcompcnent prepared as hereinafter'described.

A- silica hydrogel is separately prepared similarly as the hydratedsilica above described with the exception that the sodium chloride isomitted and a gel therefore formed. The silica hydrogel is filtered toremove the bulk of the impurities present in the reactant liquors andthe filtered hydrated silica is then suspended in a solution of zirconylchloride in an amount which will yield zirconia in the proportionsindicated above, and hydrated zirconia precipitated by the addition ofammonium hydroxide. conia hydrogel is then filtered and washed withwater acidulated with hydrochloric acid to substantially remove alkalimetal impurities. The gel is then thoroughly kneaded with the driedpowder, and the kneaded mixture extruded under Th extruded material isthen cut into short cylinders, dried and calcined similarly as for thepreparation described in Exampie 1.

Example III A silica-alumina-zirconia catalyst having the followingapproximate composition,

1003102: 5111203: 10ZrOz may be prepared according to the followingprocedure.

addition of a salt solution containing approximately one part by weightof sodium chloride in solution. Concentrated hydrochloric acid whichhydroxide. The suspension is then pumped into a tank whichcontainszirconyl chloride in solution in an amount which will yieldzirconia in the The silica-zir- Two parts of commercial water glasscontaining approximately 28% Bio: and 8 to 9% NazO is dilutedapproximately 10 times by the proportion above indicated, and thesolutions are .thoroughly mixed. The zirconia is then prepended in asolution of aluminum chloride in sufin wet condition by the removal ofalkali metal impurities, and compositing the purified silica hydrogelwith a hydrous oxide gel selected from the group consisting of alumina,zirconia, and

alumina-zirconia, mixing said powdery and hydrogel. materials andextruding.

ficient amount-to yield alumina in the proportion above indicated.Alumina hydrogel is then precipitated in the presence of the suspendedsilicazirconia composite by the gradual addition of ammonium hydroxide.This material then con"- sists of finely divided particles ofsilica-zirconia which has been embedded in alumina hydrogel and thismixture is in suitable form for extruding under high pressure accordingto the present process and is subsequently dried and calcined similarlyas for the preparation in Example I.

I claim as my invention:

1. A process for the manufacture of catalytic material suitable for usein hydrocarbon conversion reactions which comprises preparing a majorproportion of the catalystas a powdery material by precipitatinghydrated silica from a solution of an alkaline silicate by the acidfication thereof in the presence of an added component which promotesthe precipitation of the hydrated silica in said powdery form, andpurifying the hymajor proportion of the catalyst as a powdery ma terialbyprecipitating hydrated silica from a solution of an alkaline silicateby the acidification thereofin the presence of an added component'whichpromotes the precipitation of the hydrated silica in said powdery-form,and purifying the hydrated silica to substantially remove 4. A processfor the manufacture .o f catalytic material suitable for Mainhydrocarbon conversion reactions which comprises preparing a majorproportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an alkaline silicate by theacidificationthereof in the presence of an added component whichpromotes the precipitation of the hydrated silica in said powdery form,purifying to substantially remove alkali metal impurities andoompositing the purified finely divided hydrated silica with a hydrousoxide precipitate selected from the group consisting-of alumina.zirconia, and alumina-zirconia, separately preparing a minor proportionof the catalyst material as a hydrogel by copreci'pitating a hydrogel ofsilica and a metal oxide gel selected from the group consistingofalumina, zirconia, and alumina-zirconia, purifying said coprecipitatedhydrogel while in a wet condition by the removal of alkali metalimpurities, mixing said powdery and coprecipitated hydrogel materialsand extruding.

5. A process for the manufacture of catalytic material suitable for usein hydrocarbon conversion reactions which comprises preparing a majorproportion of thecatalyst as a powdery material by precipitatinghydrated silica from a solution of an alkali metalsilicate by theaddition thereto of hydrochloric acid in the presence of added sodiumchloride in sufficient concentration and at a suitable dilution toprecipitate hydrated silica in said powdery form, purifying tosubstantially remove alkali metal impurities, and compositing thepurified finely divided hydrated silica with a hydrous oxide precipitatea selected from the group consisting of alumina,

zirconia, and alumina-zirconia, separately preparing a minor proportionof the catalyst material as a hydrogel by precipitating a silicahydrogel from .a solution of analkali silicate by the acidificationthereof, purifying the silica byalkali metal impurities, separatelypreparing a minor proportion.,of the catalyst material as a hydrogel byprecipitating a silica hydrogel from a solution of an alkaline silicateby the acidification thereof, purifying the silica hydrogel while I in,the wet, condition by the removal of alkali metal impurities, andmixingsaid powdery and" hydrogel materials and extruding.

3. A process for the manufacture of catalytic material suitable for usein hydrocarbon conversion reactions which comprises preparing a majorproportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an.alkaline silicate by theacidification thereof in the presence of an added component whichpromotes the precipitation of the hydrated T silica in said powderyform, purifying to substantially remove alkali metal impurities andcom-..

consisting of alumina, zirconia, and alumina-. zirconia, andpurifyingthe composited hydratedoxides to substantially remove alkalimetal impurified silica hydrogel with ahydrous oxide gel selected fromthe group consisting of alumina, zirconia, and alumina-zirconia, mixingsaid powdery and hydrogel materials and extruding.

6. A process for the manufactureof cataLvtic material suitable for usein hydrocarbon conversion reactions which comprises preparing a majorproportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an alkaline silicate" by theacidification thereof in the presence of an added component whichpromotes precipitationv of the hysilica in said powdery form,compositing with a, hydrous oxide selected from the group purities,separately preparing a minor proportion of the catalyst material as ahydrogel by precipitating a hygrogetfrom a solution of an alkalinesilicate. by the acidification thereof, purifying the/silica hydrogelwhile in the wet condition by the removal of alkali metal impurities,and compositing the purified silica hydrogel with a hydrous oxide gelselected from the group conslsting' of alumina, zirconia, andalumina-airconia, mixing said powdery and hydrogel materials andextruding. v

7. A process for the manufacture of catalytic material suitable for usein hydrocarbon conversion reactions which comprises preparing a majorproportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an alkali metal silicate by theadditionof hydrochloric acid and in the'presence of added sodiumchloride in sufiicient concentration and at a suitable dilution so as toprecipitate the hydrated silica in said powdery form, addfllt'ering,washing and extruding the product.

'8. A" process for the manufacture of catalytic material suitable foruse in hydrocarbon conversion reactions which comprises preparing amapresence of said powdery purified precipitate in suspension by theaddition of ammonium hydroxide, filtering, washing and extruding theproduct. I

9. A process for the manufacture of catalytic material suitablefor usein hydrocarbon conver-' sion reactions which comprises preparing a majorproportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an alkali metal silicate by theaddition of hydrochloric acid and in the I presence of added sodiumchloride in sumci'ent concentration and at a suitable dilution so as toprecipitate the hydrated silica in saidpowdery form, 1 adding a solublesalt of zirconium to the suspension of, powdery hydrated silica and'precipi tating hydrated zirconia in the presence of the ,pcwderyhydrated silica, purifying said hydrated silica-hydrated zirconiacomposite to substanpension by the addition of ammonium hydroxide,

jor proportion of the catalyst as a powdery material by precipitatinghydrated silica from a solution of an alkali metal silicate by theaddition of hydrochloric acid and in the presence of added sodiumchloride in suflicient' concentration andat a suitable dilution so as toprecipitate the hydrated silica in said powdery-form, adding a solublesalt of aluminum to the suspension of powdery hydrated silica andprecipitatinghydrated alumina in the presence of the powdery hydratedsilica by the addition of an alkaline precipitant, purifying -said'hydrated silica hymina composite in a solution of a zirconium salt andprecipitating hydrated zirconia in the drated alumina composite,tosubstantially remove alkali metal impurities, suspending the purifledfinely divided hydrated silica-hydrated alutially remove alkali metalimpurities, mixing the purified powdery, hydrated silica-hydratedzirconia composite with a separately prepared alkali-metal free aluminahydrogel and extrudof catalytic material for use in hydrocarbonconversion reactions which comprises preparing a major proportion of thecatalyst as a powdery material ing the product.

10. A process for the manufacture by precipitating-hydratedsilica from asolution of an alkali metal silicate by the addition of hydrochloricacid and in the presence of, added sodium chloride in sumcientconcentration and at a suitable dilution so as to precipitate thehydrated silica in said powdery form, adding a soluble salt of aluminumto the suspension of powdery hydrated silica and precipitating hydratedalumina in the presence of thepowdery hydrated silica, purifying saidhydrated silica-hydrated alumina composite to substantially removealkali metal impurities. mixing the purified powdery hydratedsilica-hydrated alumina composite with a separatelyprecipitated alkalimetal free zir- A conia hydrogel and extruding the product.

Louis s. mssan

